Early onset and liver failure indicating poor prognosis of infant liver failure syndrome type 1

Infantile liver failure syndrome type 1 (ILFS1, OMIM #615,438), caused by leucyl-tRNA synthase 1 (LARS1, OMIM *151,350) deficiency, is a rare autosomal-recessive disorder. The clinical manifestations, molecular-genetic features, and prognosis of LARS1 disease remain largely elusive.

Three new instances of ILFS1 with confirmed variants in LARS1, encoding LARS1, were identified. Disease characteristics were summarized together with those of 33 reported cases. Kaplan-Meier analysis was performed to assess prognostic factors in ILFS1 patients.

The 3 new ILFS1 patients harbored 6 novel variants in LARS1. Among the 36 known patients, 12 died or underwent liver transplantation. The main clinical features of ILFS1 were intrauterine growth restriction (31/32 patients in whom this finding was specifically described), failure to thrive (30/31), hypoalbuminemia (32/32), microcytic anemia (32/33), acute liver failure (24/34), neurodevelopmental delay (25/30), seizures (22/29), and muscular hypotonia (13/27). No significant correlations were observed between genotype and either presence of liver failure or clinical severity of disease. Kaplan-Meier analysis indicated that age of onset < 3mo (p = 0.0015, hazard ratio = 12.29, 95% confidence interval [CI] = 3.74-40.3), like liver failure (p = 0.0343, hazard ratio = 6.57, 95% CI = 1.96-22.0), conferred poor prognosis.

Early age of presentation, like liver failure, confers poor prognosis in ILFS1. Genotype-phenotype correlations remain to be established.